15 years, 2 cracked blocks, 1 leaky indirect water heater coil
We bought our house in 2011. It had an oil-fired steam boiler of unknown age.
In January 2012, I noticed that I was adding a ton of makeup water. The block was cracked. I got a new one under warranty.
In December 2013, we switched to natural gas and got a new Weil-McLain boiler and an HTP indirect water heater. The contractor also fixed a lot of issues with the previous install (https://forum.heatinghelp.com/discussion/147386/whats-wrong-with-these-pictures).
In October 2025, the coil in the water heater sprung a leak and flooded the boiler and nearby piping (https://forum.heatinghelp.com/discussion/202257/dirty-hot-water-boiler-overfilled-related). Replaced under warranty.
Just a few days ago, the annual boiler maintenance revealed a cracked block again. Warranty expired three years ago.
What's going on? Is my town's water supply mixed with battery acid or something? What's the expected lifespan of a steam block?
Once the new boiler goes in, what should I do differently? Periodic testing and treatment of the boiler water? Whole-house water treatment?
Comments
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how much makeup water are you adding? leaky systems that are causing a lot of makeup water to be added usually corrodes boilers. a typical residential system that is not leaking should lose less than a gallon a month.
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No ,its not the water….
There was an error rendering this rich post.
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There's an automatic feeder with a meter on the current boiler. Contractors have been inconsistent about resetting it during maintenance, so I don't know the total volume of makeup water. Whenever I've looked at the meter, it's always been low, like under 10 or 20 gallons. (Edit: by "10 or 20 gallons," I don't mean that it's adding that much each year. I mean that that's what the meter shows year after year until a contractor happened to reset it. Then it would creep up again to 10 or 20 over a couple years until someone else reset it.)
There's a manual bypass, so who knows how much new water has been added as part of maintenance.
I've flushed the boiler myself once. In December 2020, my regular contractor put some additives in. This was the first time any additives were used, as far as I know. A first floor radiator puked purple brown water soon after, and then a second floor radiator did the same. I drained and refilled until the sight glass was showing clear water again, not the purple brown stuff. No idea what damage this did, but the system was never quite the same after. Just seemed off.
When the water heater leaked last year, it pushed a ton of water into the boiler and even up into the pipes. Not enough to come out the radiators, but it took many five gallons buckets to drain it back to normal level. While waiting for the replacement, I kept the bad one isolated as much as I could to keep fresh water out of the boiler, but I had to turn it on for showers and washing dishes. I'd guess I drained over 100 gallons between when I did big initial drain after first noticing the problem and then a bunch of smaller drains up kept it stable while waiting for the replacement. And who knows how much it added to the boiler before it got bad enough to be obvious.
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@saikosis , where are you located? We might know someone who can help…………………
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I'm in Southeastern Massachusetts.
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Or @Charlie from wmass but it is probably a hike for him.
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I would really search for the right contractor. no reason to keep changing boiler although S Eastern MA and RI seem to have water that eats boilers. Might consider a Burnham Steam MAx for gas fired
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It may just be bad luck.
Additionally was the block actually cracked or did it rot out ? Kind of makes a difference to me.
As far as water consumption, I'd personally keep better track of the readings, although by your description the normal use consumption seems low.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
@saikosis b4 you do anything fill the boiler over the top until the supply pipe gets cold then shut the water off and let it sit. then look for the leaks. That boiler does not look all that bad. You may have to let it sit overnight to be sure and shut the boiler switch off.
You just may have to replace a couple of push nipples ………….if you can find someone to do it.
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The tech who was here for annual maintenance last week overfilled it as part of his checkup. It leaked when it was full. The jacket was on when he showed me, so I'm not sure exactly where it's coming from. There was water in the burner tubes and underneath the unit.
I can repeat that test myself to see what's up.
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Or maybe it has seals that can be replaced. From a Weil-McLain CGa manual.
BTW if the near boiler piping is incorrect it could put stress on the boiler's block causing issues. May have lead to the premature failure of the old boiler too.
National - U.S. Gas Boiler 45+ Years Old
Steam 300 SQ. FT. - EDR 347
One Pipe System0 -
He's on the other end of the state, otherwise I would have recommended him too.
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@Steamhead Yes, he is about 10 miles from me.
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Consider switching to a forced-circulation hot water system from steam. You can zone the system out as well switching to hot water.
Lifelong Michigander
-Willie
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That's asking for trouble. Keep the steam.
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This is one-pipe steam. Switching to hot water would require a second pipe, right? That sounds impractical.
I took off the top and three of the sides of the jacket (everything except the side with the sight glass). The pictures I posted before are from the side with the electronics. The other sides look fine.
With the jacket off, I decided to try the leak test that someone suggested. The sight glass was sitting at the halfway point when I started. When the level got near the top of the glass, water starting pouring out the bottom. When I drained it back down to halfway, it stopped. Nothing came out the top, although I didn't let it sit full very long.
If the seals were bad, would it be a slow drip or a fast leak? It was much more than a drip. I can't get really get underneath well enough to see what's going on.
Charles put this boiler in originally. It's a bit far for him for regular service, but I'm seeing if I can get him out here again for the replacement.
SteamWorks had been doing the maintenance and found the leak, but it's not going to work with them for the replacement.
If anyone trusts someone else locally, please let me know.
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Try to get @Charlie from wmass to take a peak. Did Steam works say you need a new boiler or is it a gasket? how old is the boiler any warranty left?
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It was installed in 2013. It's over the 10-year warranty.
SteamWorks said new boiler. I don't know if they actually saw a crack or are just assuming based on the rate that water leaks out or if their thinking is that a new boiler is going to be almost as much time and money as fixing the old boiler.
Charles saw the pictures and thinks I need a new boiler too.
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